6598089: JDK 7: AWT often goes into busy loop when showing dialog

Summary: Preventing focus from getting in an endless loop.
Reviewed-by: son

src/share/classes/java/awt/DefaultKeyboardFocusManager.java

@@ -154,7 +154,7 @@ public class DefaultKeyboardFocusManager extends KeyboardFocusManager {
     private boolean doRestoreFocus(Component toFocus, Component vetoedComponent,
                                    boolean clearOnFailure)
     {
-        if (toFocus.isShowing() && toFocus.isFocusable() &&
+        if (toFocus != vetoedComponent && toFocus.isShowing() && toFocus.isFocusable() &&
             toFocus.requestFocus(false, CausedFocusEvent.Cause.ROLLBACK)) {
             return true;
         } else {

test/java/awt/Focus/RestoreFocusOnDisabledComponentTest/RestoreFocusOnDisabledComponentTest.java

+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+  @test      %W% %E%
+  @bug       6598089
+  @summary   Tests restoring focus on a single disabled coponent
+  @author    Anton Tarasov: area=awt-focus
+  @library   ../../regtesthelpers
+  @build     Util
+  @run       main RestoreFocusOnDisabledComponentTest
+*/
+
+import java.awt.*;
+import java.awt.event.*;
+import java.applet.Applet;
+import test.java.awt.regtesthelpers.Util;
+
+/*
+ * The bug is not reproducible on Windows.
+ */
+public class RestoreFocusOnDisabledComponentTest extends Applet {
+    Frame frame = new Frame("Frame") {public String toString() {return "FRAME";}};
+    Button b0 = new Button("button0") {public String toString() {return "B-0";}};
+    Button b1 = new Button("button1") {public String toString() {return "B-1";}};
+    volatile int nFocused;
+    Robot robot;
+
+    public static void main(String[] args) {
+        RestoreFocusOnDisabledComponentTest app = new RestoreFocusOnDisabledComponentTest();
+        app.init();
+        app.start();
+    }
+
+    public void init() {
+        robot = Util.createRobot();
+    }
+
+    public void start() {
+        frame.add(b0);
+        frame.add(b1);
+        frame.setLayout(new FlowLayout());
+        frame.pack();
+
+        frame.setVisible(true);
+
+        Util.waitForIdle(robot);
+        KeyboardFocusManager.setCurrentKeyboardFocusManager(new DefaultKeyboardFocusManager() {
+            public boolean dispatchEvent(AWTEvent e) {
+                if (e.getID() == FocusEvent.FOCUS_GAINED) {
+                    // Trying to emulate timings. b1 should be disabled just by the time it gets
+                    // FOCUS_GAINED event. The latter is a result of disabling b0 that initiates
+                    // focus auto transfer.
+                    if (e.getSource() == b1) {
+                        b1.setEnabled(false);
+
+                    } else if (e.getSource() == b0) {
+                        if (++nFocused > 10) {
+                            nFocused = -1;
+                            throw new TestFailedException("Focus went into busy loop!");
+                        }
+                    }
+                }
+                return super.dispatchEvent(e);
+            }
+        });
+        // Initiating focus auto transfer.
+        // Focus will be requested to b1. When FOCUS_GAINED is being dispatched to b1, it will
+        // be disabled. This will trigger focus restoring. Focus will be requested to b0 (the
+        // last opposite component). When FOCUS_GAINED is being dispatched to b0, it will
+        // also be disabled. However, the last opposite component (and the most recent focus owner)
+        // will still be b0. When DKFM initiates focus restoring it should detect restoring
+        // on the same component and break.
+        b0.setEnabled(false);
+
+        Util.waitForIdle(robot);
+        if (nFocused != -1) {
+            System.out.println("Test passed.");
+        }
+    }
+}
+
+class TestFailedException extends RuntimeException {
+    TestFailedException(String msg) {
+        super("Test failed: " + msg);
+    }
+}
+